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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 27 |
| 2 | 511 |
| 3 | 8624 |
| 4 | 140889 |
| 5 | 2310945 |
| 6 | 38759930 |
| 7 | 671189310 |
| 8 | 12061579816 |
| 9 | 225525484184 |
| 10 | 4392554369840 |
| 11 | 89142436976320 |
| 12 | 1884434077831824 |
| 13 | 41471340993035856 |
| 14 | 949385215397800224 |
| 15 | 22587683825903611680 |
| 16 | 557978742043520648256 |
| 17 | 14297219701868137003200 |
[1,27,511,8624,140889,2310945,38759930,671189310, 12061579816,225525484184,4392554369840, 89142436976320,1884434077831824,41471340993035856, 949385215397800224,22587683825903611680, 557978742043520648256,14297219701868137003200] |